1. Field of the Invention
The present invention relates to a keypad of a load control system for controlling the amount of power delivered to a plurality of electrical loads from an AC power source, and more particularly, to a method of easily configuring a keypad of a load control system with a new button configuration.
2. Description of the Related Art
Typical load control systems are operable to control the amount of power delivered to an electrical load, such as a lighting load or a motor load, from an alternating-current (AC) power source. A load control system generally comprises a plurality of control devices coupled to a communication link to allow for communication between the control devices. The load control system includes load control devices operable to control the amount of power delivered to the loads in response to digital messages received via the communication link or from local inputs, such as user actuations of a button. Further, the load control system often includes one or more keypads, which transmit commands across the communication link to control the loads coupled to the load control devices. An example of a lighting control system is described in greater detail in commonly-assigned U.S. Pat. No. 6,803,728, issued Oct. 12, 2004, entitled SYSTEM FOR CONTROL OF DEVICES, the entire disclosure of which is hereby incorporated by reference.
FIG. 1 is a simplified block diagram of a prior art lighting control system 10. The lighting control system 10 comprises a multi-zone lighting control unit 12 coupled between an AC power source 14 and a plurality of lighting loads 16 to individually control the amount of power delivered to, and thus the intensity of, each of the lighting loads. The multi-zone lighting control unit 12 may comprise, for example, a GRAFIK Eye® Control Unit, which is manufactured by the assignee of the present invention. The lighting control unit 12 is coupled to a communication link 18, which enables the lighting control unit to communicate with a plurality of keypads, e.g., a two-button (2B) keypad 20 and a four-scene (4S) keypad 30. The communication link 18 may be implemented as, for example, a four-wire RS-485 communication link. Each of the keypads 20, 30 is configured with a unique identifier, i.e., a unique address. Accordingly, the lighting control unit 12 is operable to transmit digital messages to the keypads using the unique addresses of the keypads. The lighting control system 10 may also comprise additional keypads, which may each have a different number of buttons at different locations on the respective front surfaces of the keypads.
FIGS. 2A and 2B are front views of the 2B keypad 20 and the 4S keypad 30. The 2B keypad 20 includes a faceplate 22 and two buttons 24A, 24B. Two visual indicators 26A, 26B, e.g., light-emitting diodes (LEDs), are located adjacent to the two buttons 24A, 24B, respectively, and provide feedback of the status of the lighting loads 16. The 2B keypad 20 may be configured with different button functionalities. For example, the buttons 24A, 24B may be configured such that an actuation of the first button 24A selects a first lighting preset (or “scene”) of the lighting control unit 12, while an actuation of the second button 24B selects a second lighting preset. Accordingly, the visual indicators 26A, 26B illuminate to indicate if the first lighting preset or the second lighting preset is selected. Alternatively, the 2B keypad 20 may be configured such that actuations of the first and second buttons 24A, 24B raise and lower the intensities of the lighting loads 16, start and stop a sequence of the lighting control unit 12, or select third and fourth lighting presets. The buttons 24A, 24B may be engraved with icons or text that are descriptive of the functions that are performed by actuations of the buttons.
Referring to FIG. 2B, the 4S keypad 30 includes a faceplate 32, four scene-selection buttons 34A, 34B, 34C, 34D, an off button 38, a raise button 39A, and a lower button 39B. Actuations of the first, second, third, and fourth buttons 34A, 34B, 34C, 34D select first, second, third, and fourth lighting presets, respectively. The 4S keypad 30 includes four visual indicators 36A, 36B, 36C, 36D, which are located next to the four buttons 34A, 34B, 34C, 34D, respectively, and illuminate to indicate whether the first, second, third, or fourth lighting preset is selected. An actuation of the off button 38 causes the lighting control unit 12 to select an off scene, i.e., one in which all of the lighting loads 16 are turned off. Actuations of the raise button 39A and the lower button 39B cause the lighting control unit 12 to respectively raise and lower the intensities of the lighting loads 16. The 4S keypad 30 may be alternatively configured such that, for example, the buttons 34A, 34B, 34C, 34D select fifth, sixth, seventh, and eighth lighting presets.
In order for the lighting control unit 12 to be responsive to the 2B keypad 20 or the 4S keypad 30, each keypad must be associated with the lighting control unit. FIG. 3 is a flowchart of a prior art association procedure 80 for associating a keypad with the lighting control unit 12. First, a user simultaneously presses and holds the top and bottom buttons on one of the keypads for three (3) seconds to enter a programming mode at step 82. For example, the user can simultaneously press and hold the first button 24A and the second button 24B on the 2B keypad 20, or the first button 34A and the off button 38 on the 4S keypad 30. Accordingly, the keypad enters the programming mode and cycles the visual indicators, i.e., individually illuminates each of the visual indicators in sequence, at step 84. At step 86, the user presses the top scene button 12A on the lighting control unit to associate the lighting control unit 12 with the keypad. At step 88, the lighting control unit 12 stores the address of the keypad in memory, so that the lighting control unit 12 is now responsive to actuations of the buttons of the keypad. At step 90, the lighting control unit 12 flashes the column of visual indicators 12B in unison to indicate that the association has been made. Finally, the user simultaneously presses and holds the top and bottom buttons on the keypad for three (3) seconds at step 92, and the keypad exits the programming mode at step 94.
FIG. 4A is an exploded perspective view of the 4S keypad 30, and FIG. 4B is a front view of a base unit 40 of the 4S keypad. While the exploded view of FIG. 4A shows the 4S keypad 30, the 2B keypad 20 has a similar assembly. The base unit 40 houses the electrical circuitry of the 4S keypad 30, which is preferably mounted on a printed circuit board (not shown). A button assembly 42 includes the buttons 34A-39B and snaps to the base unit 40, such that the buttons are operable to actuate tactile switches 44A-44I mounted on the printed circuit board inside the base unit. The base unit 40 provides seven vertically arranged tactile switches 44A-44G, such that the button assembly 42 can include up to seven vertically arranged scene-selection buttons. Alternatively, the lower most of the seven scene-selection buttons can be replaced with the raise and lower buttons 39A, 39B, which actuate the tactile switches 44H, 44I. Accordingly, a plurality of different combinations, i.e., different button configurations, may be provided on the button assembly 42.
Preferably, a plurality of backlights, e.g., LEDs (not shown), are mounted on the printed circuit board immediately behind the buttons. The backlights illuminate the buttons, such that text or icons that may be engraved on the buttons can be easily read in a dark room. The base unit 40 illuminates only the buttons that are provided on the button assembly 42, i.e., per the present button configuration of the keypad. The base unit 40 does not illuminate the backlight behind the bottom button when the raise and lower buttons 39A, 39B are provided on the button assembly 42.
A faceplate adapter 46 attaches to the base unit 40 via two screws 48. The faceplate 32 snaps to the faceplate adapter 46, such that the buttons extend through openings 50 of the faceplate. The 4S keypad 30 is adapted to be mounted in a standard electrical wallbox (not shown) via two mounting screws 52 and two mounting holes 54.
The 4S keypad 30 further comprises a dual-inline package (DIP) switch 56, which is mounted on the printed circuit board and is accessible to a user of the keypad through an opening 58 in the base unit 40. When the 4S keypad 30 is fully assembled, the DIP switch 56 is hidden from view by the button assembly 42. The DIP switch 56 includes a plurality of maintained switches, e.g., ten (10) switches, which are used to set the unique address of the 4S keypad 30 or the 2B keypad 20. The individual switches of the DIP switch 56 are either open or closed in a binary fashion to set the address. For example, the switches may be closed to indicate a logic one (1) and opened to indicate a logic zero (0). If six of the individual switches of the DIP switch 56 are used to set the address, the address may range from zero (0) to sixty-three (63), i.e., 26−1. An address of five (5) corresponds to setting the individual switches of the DIP switch 56 to 000101.
Further, the switches of the DIP switch 56 are used to set the button functionality (i.e., the functions that are selected by actuations of the buttons) and the button configuration (i.e., the number and arrangement of buttons that are provided on the button assembly 42). The base unit 40 determines which backlights to illuminate and which visual indicators to control depending upon the present button configuration. The faceplate 32 and the button assembly 42 are adapted to be removed from the 4S keypad 30 after the keypad has been shipped and installed in the field. A user may change the faceplate and the button assembly of a keypad in the field, for example, from a 4S keypad 30 to a 2B keypad 20. Because the switches of the DIP switch 56 are used to dictate the button configuration of the keypad, the individual switches of the DIP switch 56 must be changed when the button assembly 42 is changed.
Since the individual switches of the DIP switch 56 tend to be rather small and difficult to access, the process of setting the DIP switches 56 in order to configure each of the keypads can be challenging. Accordingly, the keypads may be configured incorrectly. For example, two keypads may be configured with the same address, which causes communication errors and unreliable system operation. Also, in order to change the button functionality or the button configuration, the user must remove the faceplate and the button assembly 42 to access the DIP switch 56, and must refer to a user guide in order to determine the appropriate positions of the individual switches of the DIP switch 56 to achieve the desired functionality or configuration.
Accordingly, there exists a need for a method of easily and accurately configuring a keypad, particularly when changing the button assembly and faceplate of the keypad.